The present invention relates to an IC device having a main power switching component such as a standard vertical MOSFET or a conductivity modulated MOSFET, and an auxiliary component such as a CMOS.
Recently, there has proposed an integrated circuit device (so-called power IC) in which a power VDMOS or a conductivity modulated MOSFET used as a switching element for various loads mounted on a vehicle, and other components, such as a CMOS forming a peripheral circuit of the switching element are monolithically formed in a single chip.
However, a conventional power IC of a standard vertical MOSFET type is unsatisfactory in that the possibility of the latchup of CMOS is too high, and a conventional power IC of a conductivity modulated type is unsatisfactory in that the characteristics of the conductivity modulated MOSFET are poor as compared with those of a discrete conductivity modulated MOSFET, and the fabrication process is problematical.